Process PI Loop 2-119
When the PI is enabled, the speed reference is disconnected and PI Output
has exclusive control of the commanded speed, passing through the linear
ramp and s-curve.
Configuration
To operate the drive in PI regulator Mode, the speed regulation mode must
be changed by selecting “Process PI” through the [Speed Control]
parameter.
Three parameters are used to configure, control, and indicate the status of
the logic associated with the Process PI controller; [PI Configuration], [PI
Control], and [PI Status]. Together these three parameters define the
operation of the PI logic.
1. [PI Configuration] is a set of bits that select various modes of operation.
The value of this parameter can only be changed while the drive is
stopped.
• Exclusive Mode - see
page 2-118.
• Invert Error - This feature changes the “sign” of the error, creating a
decrease in output for increasing error and an increase in output for
decreasing error. An example of this might be an HVAC system with
thermostat control. In Summer, a rising thermostat reading commands
an increase in drive output because cold air is being blown. In Winter,
a falling thermostat commands an increase in drive output because
warm air is being blown.
The PI has the option to change the sign of PI Error. This is used
when an increase in feedback should cause an increase in output.
Spd Cmd
Process PI
Controller
Linear RAmp
& S-Curve
+
+
PI Disabled
Speed Control
Spd Ref
PI Ref
PI Fbk
Slip Adder
Open
Loop
Slip
Comp
Process
PI
Spd Cmd
Process PI
Controller
Linear RAmp
& S-Curve
+
+
PI Enabled
Speed Control
Spd Ref
PI Ref
PI Fbk
Slip Adder
Open
Loop
Slip
Comp
Process
PI
To Next Page
Loading...
Need help?
General
